In VTRs, when image information is to be recorded on a magnetic tape or when the image information recorded on the magnetic tape is to be reproduced on a TV monitor, the magnetic tape is loaded by pulling out the magnetic tape accommodated in a tape cassette to a predetermined position and then helically engaging the magnetic tape around the outer periphery of the drum, with the magnetic tape being run in that state. That is, a head for recording information on the magnetic tape and for reproducing information recorded on the magnetic tape is disposed on the outer peripheral portion of the drum. As the drum rotates, the head traces the magnetic tape helically engaged around the drum at an angle, so that information is recorded on the magnetic tape or the information recorded on the magnetic tape is reproduced.
In such information handling apparatus, in which the tape is helically engaged around the drum, the tape is pulled out by tape guides whose travelling path is determined by the tape pulling out members which support the tape guides and the guide members along which the tape pulling out members slide.
U.S. Pat. No. 4,322,761 discloses a tape guide means which is capable of bringing the magnetic tape into helical contact with the drum. This tape guide means includes guide rails disposed on opposite sides of the drum and two guide pins supported on carriages movable along the respective rails. One of the rails extends in parallel to the plane on which the cassette is placed, and the other rail extends in a downward inclination from that plane. Each carriage on which the guide pin is supported moves along a groove in a side surface of the rail. While moving, the guide pin is at first inclined in a forward direction and then inclined in a forward and rightward direction.
The object of movement of the guide pins in the guide means of U.S. Pat. No. 4,322,761 is to pull out or withdraw the tape to a predetermined position which allows the tape to helically engage the drum, and no consideration is give to damage to the tape which would occur during the loading operation.
Recently, there has been a great demand for increasing the recording time (or reproducing time) of a video tape. To meet this requirement without changing the size of the cassette case, the thickness of the tapes must be reduced so as to increase the amount (length) of tape accumulated in the cassette case. Thus, there has been a tendency to reduce the thickness of the tapes.
However, reduction in the thickness of the tapes extremely reduces the strength thereof. In FIG. 14, a graph shows a relationship between the tape strength ratio and the recording time ratio, with the tape strength ratio of 20 .mu.m thickness being 1.
As can be seen from FIG. 14, as the thickness of the tapes reduces, the recording time thereof increases, however, the tape strength is extremely reduced. In recording a reproduction operation, such a thin tape may rise on a lead of the drum or be dislodged from the lead during loading. Alternatively, the tape edge may be pressed against the lead to buckle the tape, which leads to folding and damaging of the tape.
In accordance with the present invention, a magnetic tape loading device is provided which comprises a rotatable cylindrical drum having a lead provided on an outer periphery thereof, with a magnetic tape being engageable with the drum during operation of the device. A head is provided on the drum to record information on the tape or to reproduce information from the tape, with a pair of tape guides being provided for pulling out or withdrawing the tape from a tape cassette for engagement with the drum. A pair of tape pulling movable members respective support the tape guides, and a pair of guide members guide the tape guide and control the position of the tape guides so that an edge of the tape runs along the lead of the drum.
In accordance with further features of the present invention, a magnetic tape loading apparatus is provided which includes a rotatable drum having a lead on a periphery thereof, with a head being provided on the periphery of the drum for recording information on a tape or reproducing information recorded on the tape. A pair of tape guides pull out or withdraw the tape from a tape cassette to engage the tape with the drum. A tape guide returning means is provided so as to accommodate a return of the tape back to the tape cassette. A pair of tape pulling or withdrawing movable members respectively support the tape guides, with a pair of guide members having a sliding-surface thereon on which the pair of movable members are moved to thereby control a posture of the tape guide so as to be kept substantially accurately positioned from a start of a pulling out or withdrawing of the tape until when a part of the tape contacts the drum. Thus, the sliding surface is formed so that an edge of the tape continuously runs along the lead on the drum as a portion of the tape with which the tape contacts the drum increases.
In accordance with still further features of the present invention, a magnetic tape loading apparatus is provided which includes a rotatable cylindrical drum having a lead, with a head being provided on a periphery of the drum for recording information on a magnetic tape which is pulled out from a tape cassette and for reproducing information recorded on the tape. A pair of tape guides pull or withdraw the tape out of the tape cassette for enabling the tape to engage with the drum. A pair of tape pulling movable members respectively support the tape guides, with a pair of guide members being provided for guiding the tape guide so as to control the posture of the tape guides with a edge of the tape being kept along the lead of the drum. A pair of movable correcting guides control an angle through which the tape engages with the tape guide by moving with the correcting guide made contact with the contact in connection with the movement of the tape in a process of pulling out the tape.
In accordance with still further features of the present invention, a magnetic tape loading apparatus is provided which includes a drum, having on an outer peripheral portion thereof, a lead to restrict a position of a magnetic tape which engages around the drum in a peripheral direction of the drum. A head is rotatable around a center of the drum for recording information on the tape or for reproducing information from the tape. Tape guides are provided for pulling out the tape from a tape cassette in which the tape has been accommodated and for returning the tape into the tape cassette. Movable correcting guides correct an angle through which the tape makes contact with the tape guides, and tape pulling movable members support and move the tape guides. Guide members are provided along which the tape pulling movable members slide, with the guide members having a surface along which the tape pulling movable members slide. The surface is formed so that a posture of the tape guide remains from when the tape is pulled out until a part of the tape makes contact with the drum and so that an edge of the tape continuously runs along the lead on the drum as a contact angle through which the tape is brought into contact with the drum increases after the tape makes contact with the drum.
Preferably, in accordance with the present invention, the tape pulling movable members slide along the sliding surfaces provided on front and rear surfaces of the guide member. The slide surfaces change the positions of the tape guides relative to the drum to assure that an edge of the tape continuously runs along the lead of the drum.
In accordance with still further features of the present invention, a magnetic tape loading apparatus is provided which comprises a rotatable drum having a lead, with a pair of tape guides being provided for pulling out a magnetic tape accommodated in a tape cassette. A pair of first movable correcting guides correct an angle through which the tape enters and exits from the tape guides to substantially zero in connection with the movement of the tape guides. A pair of tape pulling movable members support and move the tape guides, with a pair of guide members being disposed on opposite sides of the drum. The guide members have a sliding surface along which the movable correcting guide slides, with the sliding surface being formed so as to control a posture of the tape guide with an edge of the tape being constantly maintained along the lead on the drum. A pair of second movable correcting guides are provided for correcting an angle through which the tape makes contact with the first movable correcting guides.